In recent years, a number of platinum(II) complexes, including well-known cisplatin, have been synthetized and have been reported to have antitumor activity. We, the present inventors, have synthesized some platinum(II) complexes, as disclosed, for example, in Japanese Patent Application First Publn. (KOKAI) Nos. 31648/78, 35013/80, 130992/80, 103192/81, 156416/82, 16895/82, 21697/84, 34982/85, 34983/85, 97991/85, 109521/85 and 59289/87; Japanese Patent Application Second Publn. (KOKOKU) Nos. 29957/83, 34958/85 and 41077/85 as well as U.S. Pat. Nos. 4,169,846; 4,200,583; 4,256,652; 4,255,347; 4,551,524 and U.S. patent application Ser. No. 637,463 and European Patent Nos. 1126 and 8936, European Patent Appln. Nos. 83 303659.3 and 84 305304.2
We have also synthesized some organoplatinum (IV) complexes, as disclosed,for example, in Japanese Patent Application First Publication (KOKAI) Nos. 87295/85 and 109521/85; Japanese Patent Appln. No. 48625/86, as well as U.S. patent application Ser No. 020,893 and European Patent Appln. No. 87 420061.1.
Meanwhile, it is always demanded that new, antitumor platinum complexes having any more excellent properties than the known antitumor organoplatinum complexes are created and provided for uses in therapeutic treatment of tumors.